The invention relates to headphones such as are used with telephones or radios, e.g. walkie talkies or cellular phones. The invention is particularly directed to a headphone that can be used to both send and receive audio information. In its preferred form the headphone comprises two ear pieces; a speaker (receiver) is mounted within one of the ear pieces, and a microphone is mounted within the other ear piece, such that the person wearing the headphone can both send and receive audio information without using his hands. The person's hands are free to do other things, e.g. drive a vehicle, or take down information on a pad of paper, or operate a typewriter.
Under this invention the microphone is built into one of the earpieces; it is not located in front of the person's face on the end of a cantilever arm (boom) where it might prevent the user from performing certain tasks, and where it might be subject to interference from surrounding noise.
The invention takes advantage of the fact that in human beings the vocal chords are in communication with the hearing organs, such that when a person speaks the vocal information (sound waves) travel not only out of the person's mouth but also internally against the person's eardrums. A microphone placed in close adjacency to a person's outer ear will readily pick up words being spoken by the person
A person's vocal chords are located near the top of his larynx (voice box) which connects with the person's throat. Thus, the vocal chords and ear drum are in communication with each other, such that air vibrations generated by the voice box are transmitted to the ear drum(s). When a person speaks sound waves pass through the eardrums. If a microphone is placed against the surface of a person's outer ear, i.e. against an ear lobe, it will pick up the voice-generated sounds. The present invention utilizes this phenomena.
The invention is believed useful in several situations where it is desirable for a person to both hear and speak without having to use his hands to hold a handset up to his face; e.g. telephone operators, two-way radio operators, persons operating vehicles (automobiles, airplanes, etc.), news reporters taking notes or speaking into television cameras, medical or chemical workers wearing mouth covers or respirators, or military personnel while operating guns or looking through telescopic sights. In any of these situations it is desirable that the person have his hands free, and also that the area in front of the person's face be unobstructed. The present invention achieves these objectives. The invention also is advantageous where the user is in a high noise area, or where the person desires to mask the fact that he has a microphone on his person.
There are already in existence headphones having boom-attached microphones, e.g. U.S. Pat. No. 4,420,657 to W. Larkin, U.S. Pat. No. 4,138,598 to K. Cech, U.S. Pat. No. 3,971,900 to J. Foley, and U.S. Pat. No. 4,484,029 to D. Kenney. My invention is believed to be a departure from the headphone constructions shown in these patents. I understand that there are in existence communication devices employing in-ear type microphones. However, such devices are thought to be unsuited for sending and receiving signals simultaneously; also, such devices use open type speakers which disturb other people in the immediate vicinity and/or interfere with communication privacy. The systems that I am proposing overcome the shortcomings of the prior art devices.
In a preferred form of the invention the headphone is incorporated into a fold-up telephone. This telephone includes two ear pieces hingedly attached to cushion structures that are adapted to extend along side areas of the person's head. A retractible flexible strip member interconnects the two cushion structures. This telephone unit is adapted for fold-up to a miniaturized compact mode; in the compact mode the telephone can be used as a regular handset or be carried in the person's pocket.